Jack for tractor drawn trailers and the like

ABSTRACT

A ROCKER-TYPE JACK FOR TRAILERS HAVING AN OVERALL THICKNESS OF NOT OVER ABOUT 4 INCHES HAS A GENERALLY CIRCULAR PERIMETER WITH AN EFFECTIVELY DIAMETRICAL STRUT MEANS AND A READILY RELEASABLE AXLE EMBRACING THROAT OR COLLAR AT ITS PERIMETER AT ONE END OF THE STRUT MEANS AND A FLATTENED SUPPORTING BASE DIAMETRICALLY OPPOSITE SAID THROAT, WITH THE ARCUATE PERIMETER AT EACH SIDE OF SAID BASE PROVIDED WITH TRACTION ENHANCING MEANS. IN PARTICULAR EMBODIMENTS: THE GENERALLY CIRCULAR BODY HAS REENTRANT PORTIONS IN THE TWO GUADRANTS PROXIMATE TO THE THROAT, THE TRACTION ENHANCING MEANS ARE OF PROTRUDING FORM, THE LATTER COMPRISE PROTRUSIONS EXTENDING BELOW THE LEVEL OF THE BASE, AND SPECIAL FORMS OF THROAT OR COLLAR CLOSING MEANS ARE EMPLOYED. THE THROATS OR COLLARS ROTATABLY EMBRACE THE AXLES WHEN CLOSED THEREON.

United States Patent [72] inventor George E. McCorrison 1,660,329 2/1928 Fleming 269/237X Augusta, Maine 2,347,888 5/l944 Currie A. 254/94 [21] A pplv No. 768,120 3,298,665 1/1967 Sieloff t. 254/94 gg 2 Primary Examiner-Othell M. Simpson Assi nee May M Co lnc Assistant Examiner-David R. Melton g Gardiner Mail'le A!!orney--Hall and Houghton ABSTRACT: A rocker-type jack for trailers having an overall thickness of not over about 4 inches has a generally circular [54] JACK FOR TRACTOR DRAWN TRAILERS AND THE LIKE perimeter with an effectively diametrical strut means and a 8 Chims6 Drawing Figs readily releasable axle embracing throat or collar at its perimeter at one end of the strut means and a flattened supl l Cl 254/94 porting base diametrically opposite said throat, with the arcu- [51 1 7/22 ate perimeter at each side of said base provided with traction [50] Field of Search 254/94; enhancing means In particular embodiments; the generally 269/130 131327 circular body has reentrant portions in the two quadrants proximate to the throat; the traction enhancing means are of [56] References Cm protruding form; the latter comprise protrusions extending UNITED STATES PATENTS below the level of the base; and special forms of throat or coll,364,248 1/1921 Cavanaugh .1 254/94X lar closing means are employed. The throats or collars 1,419,553 3/1922 Cox 269/130 rotatably embrace the axles when closed thereon.

(\ p A lgl A? /2 Z 2 e I /2 Y a 62f \l /2C 7 k I 09g, 5 E I I Z E /O PATENTED JUN28 1971 SHEET 1 or 2 BY M Xfi ATTORNEY PATENTEDJUN28l97| 3588.048

SHEEI 2 BF 2 BY r k ATTORNEY JACK FOR TRACTOR DRAWN TRAILERS AND THE LIKE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to rocking support jacks for motor moved vehicles (Cl. 254-94), and is particularly but not ex clusively adapted for use with round axled tractor drawn trailers and the like.

2. Description of the Prior Art Rocking support jacks of various forms have heretofore been known to the art, but have not been widely adopted, as they have either been inconvenient or hazardous to use or unduly complicated and expensive in construction.

SUMMARY OF THE INVENTION The present invention aims to provide an improved device of the class described which combines cooperating features in a manner that provides a jack of the type concerned which is simple and relatively inexpensive in construction and yet is convenient and especially safe in use. In a first embodiment of the invention, particularly but not exclusively adapted for small trailers e.g. boat trailers, camp trailers and small house trailers, the jack comprises a generally circular rocker body, having a diametrical strut or spoke means with a readily releasable but positively locking axle embracing throat or collar means at its perimeter at one end of said strut means and a flattened supporting base at the other end of said strut means, and with the arcuate perimeter at each side of said base provided with traction augmenting elements. In a second embodiment, particularly adapted for commercial box trailers and large house trailers, the generally circular structure has reentrant portions in the quadrants thereof proximate to the throat means and a plurality of radial spokes in the remaining quadrants thereof and the peripherally located axle embracing throat means is of a preferred form, whereby the device is especially adapted'for use on commercial trailers having air brake rods or conduits and air cylinders directly behind an axle without damage to such parts. The throats or collars rotatably embrace the axles when locked thereon, and the jacks are parallel sided and of an overall thickness of not over about 4 inches, thus providing for ready flat storage in a restricted space such as the tool compartment of a vehicle.

SHORT DESCRIPTION OF DRAWINGS In the accompanying drawings illustrative of presently preferred embodiments of the invention FIGS. 1 2 and 3 are side elevation, front elevation, and plan views of said first embodiment; and

FIGS. 4, 5 and 6 are corresponding views of said second embodiment.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, and particularly to the illustrative embodiment of FIGS. 1 to 3, the rocking jack comprises a generally circular jack body 10 provided with effectively diametrical strut or spoke means 11. A readily releasable but positively lockable axle embracing collar means 12 is located substantially at the circumference of the generally circular configuration of the body 10 at one end of the strut means 11, and a part of the perimeter of the generally circular confirmation of the body 10 is flattened to provide a supporting base 14 diametrically opposite the collar means 12. The body 10 has circularly arcuate body portions 15 and 16 juxtaposed to each end of the base 14, which are provided with traction augmenting elements shown in the form of transverse ribs 17 projecting radially to a greater distance than any part of the flattened base 14, and including in the form of FIGS. 1 to 3 projecting portions 17a proximate to each end of the base 14 and extending below the plane of the base 14.

The axle embracing collar means 12 comprises an upwardly open axle receiving recess 12a in the body 10 and collar closing means 12b mounted on the body 10 and swingable to bridge across the recess 12a and close the axle embracing collar 12, and finger manipulatable means 12d for securing the collar closing means in closed position and releasing the same therefrom. In the embodiment of FIGS. 1 to 3, the collar closing means 12b is in the form of a cap which is hinged to the body 10 at 12c and has a bifurcated free end l2e, and the finger manipulatable means 12d comprises a clamp screw pivotally mounted to the body at 12f and a manually operable clamp nut 12g, i.e. a knob or wing-nut, threaded on said clamp screw, said bifurcated end 12e being engageable with said clamp screw.

Most small trailers can be accommodated by one of two sizes of rocker jack of the type shown in FIGS. 1 to 3. In the smaller size the height from the base to the center of the collar opening may be about 9% inches, the diameter of the collar opening about 1% inches, and the minimum road clearance (distance from the center of the collar opening to the line'tangent to the body 10 and the end of the closed collar closing means 12b) about 3 inches. In the larger size these dimensions may be about 12% inches, 3 inches and 5 inches respectively and in both sizes the thickness of the body may be about 3% inches.

In use of the device of FIGS. 1 to 3 for elevating a trailer axle to facilitate changing a tire or the like, the collar opening 120, which is somewhat larger than the diameter of the round axle of the trailer, is slipped over the axle with the body 10 extending forwardly or rearwardly thereof, and the cap 12b is swung closed and secured by the clamp screw and knob 12c- 12d after the same are swung from the dotted line position in FIG. 1 into the solid line position shown in FIGS. 1 to 3. The tractor means is then operated to move the trailer forward or rearward, as the case may be, for a sufficient distance to effect the elevation. This is accomplished by the engagement of traction elements 17 with the ground causing the trailer axle to rock the jack and be lifted thereby until the strut 11 becomes nearly vertical, after which point the axle is lowered as the load shifts to the base 14. If the driver of the tractor does not have an observer to watch the operation, the thud of the load dropping to being the flat base in contact with the ground signals when the correct position has been reached, especially when the projections 17a are provided to accentuate such action. Furthermore, if the driver drives too far, no harm is done as the load simply rocks up onto the opposite one of the arcuate portions 15, 16 which lowers it gently to the ground in the event the motion is continued, or acts to again let the base 14 come flat to the ground if the direction of drive is then reversed. When the desired repair or service operation has been performed, the operator again simply drives the tractor portion either forward or backward until the jack has rolled out from between the axle and the ground, after which simple manual operation of the members of the assembly 12 disengages the rocker jack from the axle. The extension of the traction elements 17 over arcs of about 60 at each end of the base 14 assures against slippage and dropping of the vehicle from the jack during the aforesaid operations.

In the embodiment of FIGS. 4 to 6 the parts corresponding to those of FIGS. 1 to 3 are indicated by the same reference numerals raised by 100. In this form the collar closing means l12b is in the form of a chain and one or more end links of the chain constitute an apertured end engageable with the clamp screw 112d. Upward swinging of the clamp screw 112d allows the knob 1123 to be removed and facilitates the engagement of the chain link with the clamp screw and the securement thereof by replacement of the finger knob 112g. In this embodiment the generally circular structure has reentrant portions 1100 in the quadrants thereof proximate to the collar means 112. These provisions facilitate attachments of the device to axles having other structures in close proximity thereto, and adapt the jack for rocking movement without damage to such proximate structures. Suitable dimensions for the device of FIGS. 4 to 6 for handling most large trailers are: height 24 inches, collar radius 2% inches, minimum road clearance 3 inches, thickness 4 inches.

While there have been described herein what are at present considered preferred embodiments of the invention, it will be obvious to those skilled in the art that modifications and changes may be made without departing from the essence of the invention. It is therefore to be understood that the exemplary embodiments are illustrative and not restrictive of the invention, the scope of which is defined in the appended claims. and that all modifications that come within the meaning and range of equivalency of the claims are intended to be included therein.

lclaim:

1. A rocking jack for engagement with an axle of a tractor drawn trailer or the like, said jack comprising:

a. a generally circular jack body having an overall thickness not over about 4 inches and provided with effectively diametrical strut or spoke means therein;

b. a readily releasable but positively lockable axle embracing collar means located substantially at the circumference of said generally circular body at one end of said strut means and sized to rotatably embrace said axle when locked;

c. a part of the generally circular conformation of the body being flattened to provide a supporting base diametrically opposite said collar means with circularly arcuate body portions juxtaposed to each end of said base; and

d. said circularly arcuate body portions over arcs of about 60 at each end of said base being provided with traction augmenting elements.

2. A rocking jack as defined in claim ll wherein said traction augmenting elements project substantially radially from said arcuate body portions and include projecting portions proximate to each end of said base and extending below the plane of said base.

3. A rocking jack as defined in claim 1, in which said axle embracing collar means comprises an upwardly open axle receiving recess in said body, and collar closing means mounted on said body and swingable to bridge across said recess and close the axle embracing collar means, and finger manipulatable means for securing said collar closing means in closing position and releasing the same therefrom, said collar and closing means when closed, rotatably mounting said collar on said axle.

A rocking jack as defined in claim 3, said finger manipulatable means comprising a clamp screw pivotally mounted to said body and a manually operable clamp nut threaded on said screw.

5. A rocking jack as defined in claim 4, said collar closing means comprising a cap hinged to said body and having a bifurcated free end engageable with said clamp screw.

6. A rocking jack as defined in claim 4, said collar closing means comprising a chain secured to said body and having link means at its free end engageable with said clamp screw.

7. A rocking jack as defined in claim 1, wherein the generally circular structure has reentrant portions in the quadrants thereof proximate to said collar means.

8. A rocking jack as defined in claim 1, wherein the generally circular body structure has reentrant portions in the quadrants thereof proximate to said collar means and a plurality of radial spokes in the remaining quadrants thereof. 

